5Highly tuned Arcam Alpha CD playerUpgrading an original Arcam Alpha


This old stal­wart dates back in design to about 1989 and I believe mine was made in 1991.  The Arcam Alpha uses one of the first DAC chips around, the fam­ous TDA1541(A).  Here’s a good page ded­ic­ated to play­ers fea­tur­ing this chip: Lamp­iz­at­or guy.  The author of that site is fam­ous in DIY circles but misses a few import­ant tricks when modi­fy­ing CD players.

Sec­tions to upgradeArcam Alpha CD in highly tuned state

I tend to think of CD play­ers as offer­ing three main areas for mak­ing sub­stan­tial sound qual­ity improve­ments: power sup­plies, clock­ing, out­put stage. Many novice upgraders nev­er pro­gress bey­ond fet­tling the ana­logue out­put sec­tion of a CD play­er.  This is a shame because the really big gains typ­ic­ally come from improv­ing power sup­plies and clock arrange­ments.

Power sup­plies

The Alpha is bet­ter than some as stand­ard, fea­tur­ing two power trans­formers and a 6 x 1000uF bank of smooth­ing caps for the DAC & op-amps.  It seems clear upon intern­al inspec­tion that Arcam have taken a gen­er­ic Philips PCB and power trans­former etc, then added their own DAC / out­put stage board which is powered by a second trans­former.  Sadly this trans­former is prone to mech­an­ic­al buzz­ing (a side effect of poorly con­struc­ted frame trans­formers).  One of my earli­er modi­fic­a­tions was to replace this with a tor­oid­al trans­former of the same sec­ond­ary voltages (17.5V — 0V — 17.5V).  The main PCB’s PSU caps power everything oth­er than the DAC chip and out­put op-amps.  Most, if not all, of these should be replaced, not only to improve sound qual­ity but also because the elec­tro­lyte in the caps could be dry­ing up after 20+ years!  It is fash­ion­able and indeed seems bene­fi­cial to change rec­ti­fier diodes with soft-recov­ery types, usu­ally “schot­tky”.  In my opin­ion this is a safe modi­fic­a­tion on digit­al sup­plies but may worsen the sound on ana­logue supplies.

To take things to a whole oth­er level it’s easi­est to mount some extra sup­plies off-board and run wires to it.  Remotely feed­ing my Alpha I have sup­plies for my new out­put stage, the digit­al fil­ter (SAA7220), decoder (SAA7310), servo driver chips as well as a trans­former ded­ic­ated to the after-mar­ket clock and the RAM IC.  The rec­ti­fic­a­tion and smooth­ing for clock sup­ply is on-board as I found on a pre­vi­ous pro­ject clock power sup­plies can cause issues when moun­ted externally.

For now I’ll just wrap this sec­tion up by say­ing use good qual­ity, LARGE capa­city caps on the DAC smooth­ing and you’ll be richly rewarded.


For a long while it’s been a pop­u­lar modi­fic­a­tion to “re-clock” the DAC chip in your CD play­er.  Repla­cing the stand­ard tim­ing crys­tal with a low-jit­ter clock can be a subtle improve­ment or a pro­found one, depend­ing on the cir­cum­stances.  There are vari­ous after-mar­ket vendors of such clocks such as Tent Labs, Audi­ocom, LC and, more recently, Fidel­ity Audio.

Bey­ond DAC re-clock­ing, there are oppor­tun­it­ies to feed a “clean” clock sig­nal to oth­er parts of a CD play­er such as the decoder chip, digit­al fil­ter and maybe even parts of the servo.  In the Alpha I have so far fed 4 clock feeds from my Fidel­ity Audio C2 mas­ter clock.  Two of these re-clock pins on the DAC, one does the digit­al fil­ter and the oth­er the decoder.  Three of these are 11.2Mhz, the oth­er is 5.6Mhz (the main clock divided by two, which is avail­able on this par­tic­u­lar product).

If you go down this path you’ll be glad you did!

Out­put stage

The last thing I want to talk about is the out­put stage.  Arcam did a fair job on the power sup­plies, a typ­ic­ally poor job on the clock­ing and again let us down a little bit with the main out­put sec­tion, but there are far worse!  The out­put stage uses two single op-amps per chan­nel and some good qual­ity caps to fil­ter HF noise.  There’s noth­ing intrins­ic­ally wrong with op-amps but the ones avail­able at the time wer­en’t very good.  It’s pos­sible to upgrade these 4 op-amps and the res­ults would be good.  I tried to replace the final pair of op-amps with some Burr Brown OPA627, but I did­n’t get sound.  Without look­ing fur­ther into it I think it may be because they are not unity gain stable, mean­ing they can­not work purely as a “buf­fer”, they must amp­li­fy the signal.

The reas­on I looked no fur­ther was because I was build­ing up a whole new out­put stage using a PCB I sourced from the DIYAudio.com for­um.  This was designed by Nel­son Pass, a man fam­ous for his large class A amp­li­fi­er designs sold under the name Pass Labs.  This out­put stage was a quantum leap for­ward in son­ics!  Espe­cially so if, like me, you enjoy a warm full-bod­ied sound.  The power sup­ply for this is off-board.


I will add to this art­icle as I think of improve­ments but it’s very dif­fi­cult to fit it all in as there is SO MUCH that can be done to an old CD play­er!  I would just hope to whet a few appet­ites of those seek­ing the elu­sive “per­fect sound forever” that Philips prom­ised us with the advent of the Com­pact Disc.  If you enjoyed this art­icle and want to request more detail on one par­tic­u­lar area then please drop in a com­ment, I’ll be sure to see it and respond.

Got some thoughts of your own? Indulge yourself below by commenting! If you would like to subscribe please use the subscribe link on the menu at the top right. You can also share this with your friends by using the social links below. Cheers.

Leave a Reply



Hi, I know this is an old art­icle but its what Ive been look­ing for. May I ask where you sourced the 17.5v‑0–17.5v transformer?
Would a 18v 0 18v be a substitute?


Bravo Simon — like the site and use­ful down­loads too 



Thanks Andrew! There’s lots I want to talk about on here, when I get around to it. Funny how I only just saw your com­ment 3 weeks later..


Hi bought an old but per­fect Arcam Alpha CD play­er, it sounds good but I would like to upgrade it little by little, which is the first step of the three?…instead of chan­ging the op amps with some­thing new­er what do you think about to put two trans­formers in place of the op amps?…
Thank you


Hi, would an 18v 0 18v trans­former be OK to use? Could I ask where you got the 17.5v one?